In this paper the author analyses the different weaknesses of the HVAC systems in case of air contamination by a deliberate pollution of the inducted air due to vandalism, terrorism or any other motives.To prevent that danger he gives some advice about HVAC installation :A safe air intake is necessary, but the intake grille for ventilation must be inaccessible from outside the building and its position at ground level unsuitable.Air dampers must have effective sealing and be closed in the event of a bioterrorist attack.Recirculation systems can be contamined too from a source within the bui
A numerical investigation has been made on the effect of thermal and mass buoyancy forces on the development of laminar mixed convection between vertical parallel plates with uniform wall heat and mass fluxes. Some parameters such as velocity, temperature and concentration are presented and their incidence on heat and mass transfer between the plates is discussed for both positive and negative values of the buoyancy ratio. Results and discussions are presented.
A study on the effect of air temperature on productivity was carried out in telecommunications offices with an observational approach in call centre 1 and an intervention approach in the second call center by installing cooling units.The study shows that the productivity can be reduced by 5 to 7 % when the indoor temperatures increase.
This paper presents the modeling of convective flows based on lattice Boltzmann methods in combination with a large eddy turbulence model. The used example is complex and three-dimensional.
That study aims at proving that the use of low-polluting building materials leads to an improvement of the air quality. For the experiment the space of an office qualified as low polluting has been altered by introducing indoor pollution sources (such as linoleum, wooden shelves, books and paper documents) and an outdoor air supply rate altered too. The concentrations of VOCs were measured in those different conditions along with the perception of the air quality assessed by a panel of 30 female subjects.
A large opening has to be designed at the bottom of a Void (light-well in high-rise apartment building) in order to keep the indoor air quality (IAQ) acceptable, because of the exhaust gas discharge of the gas water-heater. This paper presents a simple calculation method of the ventilation rate induced by wind force and thermal buoyancy through openings at the bottom, along with heat sources such as water-heaters.
There is a relationship between geometric room parameters and the air flow patterns produced by mechanical ventilation systems. Experimental measurements of indoor air flows in a one-tenth sub-scale model room were made and compared to numerical simulations. The results show how obstructions can influence the air flow and contaminant transport in a room.
Over the past decade, there has been extreme media attention to issues about mold and allegedlyadverse effects. Unfortunately, misinformation about mold and health effects abounds and oftenthe public is led to believe that exposure to mold is a dangerous event. This paper presentscommon points of misinformation about mold and health. Scientific documentation to refute themisinformation is presented.
A field survey was carried out to evaluate the thermal comfort perception of the occupants of a naturally ventilated public housing in Singapore to find out if that environment meets the Ashrae standard 55's 80 % criteria of acceptability.That survey also examined the adaptive behavior of the occupants in the use of windows, fans, and air-conditioning . Whether the thermal perception was influenced by different sessions of the day, building height and flat types was also part of the study.
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